r-faq Archives - Page 4 of 7

Test if characters are in a string

I’m trying to determine if a string is a subset of another string. For example: chars <- "test" value <- "es" I want ...

May 11, 2022
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How does one reorder columns in a data frame?

How would one change this input (with the sequence: time, in, out, files): Time In Out Files 1 2 3 4 2 3 ...

May 10, 2022
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How can I trim leading and trailing white space?

I am having some trouble with leading and trailing white space in a data.frame. For example, I look at a specific row in ...

May 9, 2022
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Sample random rows in dataframe

I am struggling to find the appropriate function that would return a specified number of rows picked up randomly without replacement from a ...

May 8, 2022
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Side-by-side plots with ggplot2

I would like to place two plots side by side using the ggplot2 package, i.e. do the equivalent of par(mfrow=c(1,2)). For example, I ...

May 7, 2022
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Elegant way to check for missing packages and install them?

I seem to be sharing a lot of code with coauthors these days. Many of them are novice/intermediate R users and don’t realize ...

May 7, 2022
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Why is `[` better than `subset`?

When I need to filter a data.frame, i.e., extract rows that meet certain conditions, I prefer to use the subset function: subset(airquality, Month ...

May 6, 2022
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Extracting specific columns from a data frame

I have an R data frame with 6 columns, and I want to create a new dataframe that only has three of the ...

May 6, 2022
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How to add leading zeros?

I have a set of data which looks something like this: anim <- c(25499,25500,25501,25502,25503,25504) sex <- c(1,2,2,1,2,1) wt <- c(0.8,1.2,1.0,2.0,1.8,1.4) data <- data.frame(anim,sex,wt) ...

May 6, 2022
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